# CVE-2026-98364: xfrm: hold net_device reference under RCU in bundle creation

> A use-after-free in the Linux kernel's xfrm bundle creation allows attackers to trigger memory corruption, potentially leading to code execution or privilege escalation.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 6 Oct 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-106296, BELL-CVE-2026-98364, DEBIAN-CVE-2026-98364, GHSA-qcc9-56m7-mpxg, UBUNTU-CVE-2026-98364

## What is CVE-2026-98364?

CVE-2026-98364 is a high-severity use after free vulnerability in Linux, published on 6 Oct 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

xfrm: hold net_device reference under RCU in bundle creation

xfrm_bundle_create() and xfrm_create_dummy_bundle() read dst->dev into
a local pointer without taking a device reference, then pass it to
xfrm_fill_dst(). A concurrent RTM_DELLINK replaces dst->dev via
dst_dev_put() and frees the old net_device, causing a use-after-free
when xfrm6_fill_dst() later dereferences the stale dev pointer.

  BUG: KASAN: slab-use-after-free in xfrm6_fill_dst+0x82c/0x860
  (net/ipv6/xfrm6_policy.c:86 netdev_hold())
  Read of size 8 at addr ffff8880142fe588 by task exploit/153
  Call Trace:
   xfrm6_fill_dst+0x82c/0x860
   xfrm_resolve_and_create_bundle+0x21d4/0x2bd0
   xfrm_lookup_with_ifid+0x485/0x1640
   ip6_dst_lookup_flow+0x19b/0x1e0
   udpv6_sendmsg+0x1443/0x2dd0

Fix this by reading dst->dev via dst_dev_rcu() and keeping the RCU
read-side critical section active until xfrm_fill_dst() has taken the
required device references.

## Which versions are affected by CVE-2026-98364?


## How do I fix CVE-2026-98364?

Apply the vendor's patch.

## Is CVE-2026-98364 being exploited?

There is no known exploitation of CVE-2026-98364 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98364 and fix it if it is affected.

What it is: CVE-2026-98364 is a high-severity use after free vulnerability in Linux, published on 6 Oct 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-98364 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-98364/ (Markdown: https://insights.sbomify.com/CVE-2026-98364/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98364
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98364
- OSV: https://osv.dev/vulnerability/CVE-2026-98364

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98364/
Summaries are generated and may contain mistakes; the official description above is the record.